Isotretinoin is a retinoid (also known as 13-cis retinoic acid). Owing to its low water solubility, the oral bioavailability of isotretinoin is low. PCT Publication No. WO 00/25772 discloses that the presently marketed formulation of isotretinoin, i.e., Accutane®, contains isotretinoin at a mean particle size of about 100 μm resulting in only 20% oral bioavailability. Therefore, this application discloses a formulation of isotretinoin having a reduced particle size, thereby enhancing the oral bioavailability.
U.S. Pat. Nos. 7,435,427 and 8,367,102 cover the marketed formulation of Absorica®. These patents disclose capsules comprising a semi-solid suspension of isotretinoin containing at least two lipidic excipients, one having an HLB value equal to or greater than 10 and the other being an oily vehicle. These patents are based on the use of the “Lidose technology” to provide a formulation of isotretinoin with enhanced bioavailability.
The oral bioavailability of a drug is affected by various factors which include the aqueous solubility, first pass effect, or food-effect. The low water solubility of isotretinoin affects its oral bioavailability. Therefore, there is a need to develop an oral pharmaceutical composition of isotretinoin having enhanced bioavailability. The present inventors have developed an oral pharmaceutical composition of isotretinoin having enhanced bioavailability in comparison to the already marketed formulations of isotretinoin, i.e., Roaccutane® and Absorica®/Epuris™. This enhancement in bioavailability of isotretinoin by the present invention can be directly correlated to dose reduction of isotretinoin, which would be highly beneficial in the case of isotretinoin, which is a teratogenic drug.